Zinc oxide surface-functionalized PCL/graphene oxide scaffold: enhanced mechanical and antibacterial properties

Multifunctional scaffolds for biomedical applications: Crafting versatile solutions with polycaprolactone enriched by graphene oxide

The pressing need for multifunctional materials in medical settings encompasses a wide array of scenarios, necessitating specific tissue functionalities. A critical challenge is the occurrence of biofouling, particularly by contamination in surgical environments, a common cause of scaffolds impairment. Beyond the imperative to avoid infections, it is also essential to integrate scaffolds with living cells to allow for tissue regeneration, mediated by cell attachment. Here, we focus on the development of a versatile material for medical applications, driven by the diverse time-definite events after scaffold implantation. We investigate the potential of incorporating graphene oxide (GO) into polycaprolactone (PCL) and create a composite for 3D printing a scaffold with time-controlled antibacterial and anti-adhesive growth properties. Indeed, the as-produced PCL-GO scaffold displays a local hydrophobic effect, which is translated into a limitation of biological entities-attachment, including a diminished adhesion of bacteriophages and a reduction of E. coli and S. aureus adhesion of ∼81% and ∼69%, respectively. Moreover, the ability to 3D print PCL-GO scaffolds with different heights enables control over cell distribution and attachment, a feature that can be also exploited for cellular confinement, i.e., for microfluidics or wound healing applications. With time, the surface wettability increases, and the scaffold can be populated by cells. Finally, the presence of GO allows for the use of infrared light for the sterilization of scaffolds and the disruption of any bacteria cell that might adhere to the more hydrophilic surface. Overall, our results showcase the potential of PCL-GO as a versatile material for medical applications.

EVA and SEBS-MA copolymers incorporated silicone rubber/SEBS blends: improvement of mechanical and thermal properties

Enhancing the mechanical and thermal properties of Silicone rubber (SR)/SEBS blends using various compatibilizers opens the opportunity for such new blends to meet the market desire. For this purpose, blends with a 1:1 ratio of SR and SEBS are prepared with different amounts of EVA or SEBS-MA copolymers as compatibilizer. Mechanical properties of the blend are enhanced by adding EVA and SEBS-MA. Addition of 6 phr EVA profoundly improves the tensile strength from 7.70 to 10.06 MPa. Thermogravimetric analysis reveals that the presence of compatibilizer can improve the thermal stability of the blend, especially its initial degradation temperature (T5%). T5% of the blend increases from 376 to 390 °C when comprising 6 phr SEBS-MA. Morphology of the blends is investigated using SEM and AFM. Results of the relaxation modulus curves obtained by rubber process analyzer (RPA) demonstrate that the amount of relaxation in the uncured blends is higher than the cured ones. A comparison of the relaxation of the blends indicates that the relaxation modulus of the SEBS-MA compatibilized blends is enhanced more than other blends after curing. Further investigations indicate that the compatibilized blends exhibit higher tear energy and lower compression set.

Highly resilient porous polyurethane composite scaffolds filled with whitlockite for bone tissue engineering

The present work is intended to provide a base for further investigation of the composite scaffolds for bone tissue engineering, and whitlockite/polyurethane (WH/PU) scaffolds, in particular. WH Ca₁₈Mg₂(HPO₄)₂(PO₄)₁₂ was successfully prepared by means of a chemical reaction between Ca(OH)₂, Mg(OH)₂ and H₃PO₄. WH/PU scaffolds were synthesized via in situ polymerization. Synthesized WH particles and WH/PU composite scaffolds were characterized using FTIR, XRD, SEM and EDS. The porosity of scaffolds was calculated by the liquid displacement method. The water contact angle of scaffolds was tested. Mechanical characterization of WH/PU composite scaffolds was evaluated according to monotonic and cyclic compression examination. MC3T3-E1 cells were employed to evaluate the cytocompatibility of scaffolds. The results showed that WH and PU were completely integrated into composite biomaterials. The maximum compressive strength and elastic modulus of WH/PU composite scaffold reached up to 5.2 and 14.1 MPa, respectively. WH/PU composite scaffold had maximum 73% porosity. The minimum contact angle of WH/PU composite scaffold was 89.16°. WH/PU composite scaffolds have a good elasticity. Cyclic compression tests showed that scaffold could recover 90% of its original shape 1 h after removing the load. WH/PU composite scaffolds exhibited a high affinity to MC3T3-E1 cells. WH/PU composite scaffolds significantly promoted proliferation and alkaline phosphatase activity of MC3T3-E1 cells when compared to those grown on tissue culture well plates. It is suggested that the WH/PU scaffolds might be suitable for the application of bone tissue engineering.